Share this on WhatsApp We’re all familiar with muscle conditioning or deconditioning that happens in response to exercise or lack of it. But when an active lifestyle—or, by contrast, that of a couch potato—is sustained over evolutionary timescales stretching for thousands or millions  of years, that leads to dramatic changes in muscle mass, metabolism and … Continue reading Evolution Turns These Knobs to Make a Hummingbird Hyperquick and a Cavefish Sluggishly Slow